sciencehabit writes: Drive around Washington, D.C., and the phrase "passing gas" takes on a whole new meaning. Researchers who mapped methane concentrations on the streets of the nation's capital found natural gas leaks everywhere, at concentrations of up to 50 times the normal background levels. The leaking gas wastes resources, enhances ozone production, and exacerbates global warming—not to mention powering the city's infamous exploding manholes.